My friend’s flight home from Palma to London was cancelled yesterday (Sunday 27 Aug)

Being the end of the holidays, the next available flight with seats (and just 2 at that) was Thursday 31 Aug. No seats on other airlines either so no option to book elsewhere and claim back.

My friend accepted the flight on 31st in MMB in order to get something secured before that date too was sold out.

If something sooner now becomes available, are they able to request BA change them onto it? My understanding was you can have 1 free of charge change in response to a cancellation, however common sense in this scenario would suggest that BA should allow the customer to come home closer to their original flight date if space opens up.

Wondering if anyone has any experience of this?